Conventionally, a probe apparatus has been used to perform a probe test for inspecting electric characteristics of a semiconductor chip by bringing probes (probe needles) of a probe card into contact with electrode pads of the semiconductor chip. Such a probe apparatus includes a prober chamber having a probe card and a mounting table; and a loader chamber equipped with a substrate transfer mechanism configured to transfer a wafer between a loading port accommodating a wafer carrier (FOUP) therein and the prober chamber.
The substrate transfer mechanism takes out a wafer from the wafer carrier loaded into the loading port. Then, after pre-alignment of the wafer is performed by a pre-alignment mechanism installed within the loader chamber or a pre-alignment mechanism installed at the substrate transfer mechanism, the substrate transfer mechanism transfers the wafer onto the mounting table within the prober chamber. Further, there is also known a probe apparatus having a loader chamber equipped with a reading mechanism (e.g., an optical character reading (OCR) mechanism) for reading information such as a bar code or characters recorded on a wafer held on a substrate transfer mechanism (see, for example, Patent Document 1).
Further, there is also known a probe apparatus in which a plurality of prober chambers are provided for a single loader chamber. In such a probe apparatus, to reduce a footprint and a transfer height by a transfer robot within a clean room, a FOUP (wafer carrier) 20 is placed at a position higher than that of each prober chamber 21, as illustrated in FIG. 9. In such a configuration, a wafer taken out of the FOUP 20 is lowered to a height corresponding to a loading/unloading port 23 of the prober chamber 21 by a substrate transfer mechanism 3 installed within the loader chamber 1. Then, the wafer is transferred in horizontal direction by the substrate transfer mechanism 3 to be loaded into or unloaded from the prober chamber 21 through the loading/unloading port 23. In such a probe apparatus, an OCR mechanism 60 is installed below a mounting unit for the FOUP 20.
In the probe apparatus having the mentioned configuration, to transfer the wafer taken out of the FOUP 20 into the prober chamber 21, the substrate transfer mechanism 3 is first lowered to a height corresponding to the OCR mechanism 60 (as indicated by an arrow A of FIG. 9), and the substrate transfer mechanism 3 is then moved in horizontal direction toward the OCR mechanism 60 (as indicated by an arrow B of FIG. 9). Then, after characters recorded on the wafer is read by the OCR mechanism 60, the substrate transfer mechanism 3 is returned back to its previous horizontal position (as indicated by an arrow C of FIG. 9) and then is lowered again to a height corresponding to the loading/unloading port 23 of the prober chamber 21 (as indicated by an arrow D of FIG. 9). Thereafter, the substrate transfer mechanism 3 transfers the wafer horizontally to the front of the loading/unloading port 23 of the prober chamber 21 (as indicated by an arrow E of FIG. 9).
Meanwhile, there has been used a substrate transfer mechanism having, e.g., two arms for holding two substrates as substrate holding members. While a probe test for a wafer is being performed in a prober chamber, a next wafer to be tested is taken out by one of the arms, and pre-alignment of the next wafer is performed. Then, upon the completion of the test for the wafer in the prober chamber, the tested wafer is received by the other one of the arms, and the next wafer to be tested held on the one arm is transferred onto the mounting table within the prober chamber.
The wafer held on the arm of the substrate transfer mechanism is transferred onto the mounting table within the prober chamber through the loading/unloading port provided in a front side of the prober chamber. Here, the substrate transfer mechanism needs to be stopped at a position in front of each prober chamber.
Meanwhile, there is also known a probe apparatus having a single substrate transfer mechanism and a plurality of prober chambers (see, for example, Patent Document 2). In such a probe apparatus, the substrate transfer mechanism is configured to be moved in left and right directions on a rail provided in front of the plurality of prober chambers that are arranged in a straight line. As depicted in FIG. 10, to transfer a wafer into each prober chamber, a substrate transfer mechanism 3 needs to be moved to a position in front of the loading/unloading port of each prober chamber. In FIG. 10, reference numerals 35 and 36 are first and second arms for holding wafers thereon in the substrate transfer mechanism 3.    Patent Document 1: Japanese Patent Laid-open Publication No. 2007-329458    Patent Document 2: Japanese Patent Laid-open Publication No. H3-289152
In the aforementioned probe apparatuses, throughput needs to be further improved so as to perform test of target substrates efficiently. Further, in the above-described probe apparatuses, their footprint within the clean room needs to be further reduced. Moreover, the atmosphere within the prober chamber needs to be maintained clean so as to perform the test of the target substrates in a clean atmosphere.